NPR Shader flickering

[scott8933]

Hello everyone,

I'm using the NPR shader to do an outline render, it has a little bit of solid shading on the edges of the objects right now, which is fine except that it flickers throughout the animation. Flickers, as in parts of it (in strips, inconsistently) will just drop out for a frame then reappear as normal in the next frame.

I can probably blend it out in AE, but I'd rather have it render correctly in the first place. Anyone know the cause and solution?

The attached files show the correct frame in all black and the next frame with a portion dropped out, highlighted in red.

Thanks.

[CyberMODE]

Hello Scott:

Dont have a easy solution, NPR get the normals info and paint the perpendicular poligons to camera with shadow zone. No same position all time.

If can add more poligons with dicer can solve a bit...

Thanks

[scott8933]

I could understand (and fix!) if the problem were consistent, but the camera is moving very slowly across the scene, and the flashes appear out of nowhere for just a frame. Not always on the whole scene either, sometimes just the lower half. Might be related to the bucket size? I'm on a borrowed box with not much ram, I haven't actually changed Camera's stock memory settings.

I tried a few things, changing lights, changing the camera angle slightly, etc. It always pops at the same frames.

Solution 2, I tried doubling the frame rate (if nothing else I can frame blend the shadows with this pass and minimize the flashes) and it still did it during the same frames. Again sometimes the lower half only.

Hello Scott:

Dont have a easy solution, NPR get the normals info and paint the perpendicular poligons to camera with shadow zone. No same position all time.

If can add more poligons with dicer can solve a bit...

Thanks

[scott8933]

Problem fixed by switching to the full version of NPR; I would have preferred to have figured out what was causing it, but no time.

Things I tried that had no effect:

-Change camera position and angle (slightly)

-Change light setup (more lights, less lights, change light position, change intensity)

-Change object's luminance, diffuse, specular

-Change settings in NPRLight

-Change frame rate from 24 to 48

-Change from Raytrace to Phong

Every time, same result. Every 20 or so frames (at random, no pattern I could see) either all or some of the shaded area would not shade. Next frame it would come right back. Sometimes only half the frame would drop out, and it appeared to correspond to the bucket size but it was rendering too fast to be sure. Camera was moving very slowly, no sharp movements in the scene.

When I changed to 48 fps, it dropped out at the same frames and occasionally the dropouts would extend for half a frame before or after.

No more time spent troubleshooting.

[Tomas Egger]

Ola Scott,

Great you found the problem, a simple new NPR Full build :)

Thanks

Tom

[scott8933]

Given more time I'd like to have figured out the solution for the Lite build, since not everyone has the option to switch to the full version... and actually I like the easier-to-use Lite option panel. But as long as it works I'm happy.

It seems like it would be easy to analyze since it was "random" (in time) but completely repeatable. Also, I forgot to mention but just remembered, the dropout was effecting all visible geo in the scene, not just one or two models, and I'll have to double check but I think it did it when I replaced a model with an Ubershape as a test.

-Scott

Ola Scott,

Great you found the problem, a simple new NPR Full build :)

Thanks

Tom